[Invincibly Ignorant]

This does not mean that there will always be a king in Israel (obviously). If the nation is disobedient, there will be no king or kingdom. But, this does not mean that God would put someone else on the throne other than one of Solomon's descendants. They will be "chastened", but, unlike Saul, this line will not lose the right to kingship.

By the way, this line lost kingship after being carried away into Babylon.

[malakhi]

By the way, this line lost kingship after being carried away into Babylon.

Who is the true king of Gondor? That they lost the kingship doesn't mean they lost the right to kingship. Except for Jeconiah's descendants, but this is stated specifically in scripture. Others of the line of David, not through Jeconiah, continued to carry the promises of God made to David and Solomon.